In atmospheric-type gas burners, as used in a combustion apparatus such as a furnace, air is drawn into the mixing chamber by the aspirating action of the gas flow and is mixed with the gas to provide a combustible gas-air mixture. It is important to provide uniform mixing of the gas and air to obtain the optimum combustion characteristics and in the past, various types of mixing devices, such as vanes, fans, baffles, and the like have been used to achieve the desired mixing of the gas and air.
It is also known to utilize a target at the downstream end of the mixing chamber. The conventional target takes the form of a screen or disc that partially closes off the downstream end of the mixing chamber and generates a back pressure and spreads the combustion mixture to provide a short axial flame pattern.